IdentifyUpstreamOriginNodes

Id 1.3.6.1.4.1.33097.7.0.3.60001

Given a Digraph#1.3.6.1.4.1.33097.1.0.14 G=(V, E) with V Vertices(aka Nodes#1.3.6.1.4.1.33097.1.0.12.0) and E Edges#1.3.6.1.4.1.33097.1.0.12.1. Identify the number of UpstreamOriginNodes#1.3.6.1.4.1.33097.1.0.13.1.

The data will be provided in pairs of letters, each letter representing a NodeId#1.3.6.1.4.1.33097.1.0.12.0.0. In addition, an AdjacencyMap class will be provided as follows.

Code Listing

Performance

Time Cost

O(v log log v)

Space Cost

O(v)

Examples

Example A / #001

Input

a → d
e → f
d → f

Output

2

Example B / #002

Input

a → d
d → f
d → h

Output

1